Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.22 (cdc2)
 8,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cdk9 is a key elongation factor for RNA transcription and functions by phosphorylating the C-terminal domain of RNA polymerase II. Here we present direct evidence that cdk9 is important for cancer cell survival and describe the characterization of the potent cdk9 inhibitor CDKI-73 in primary human leukemia cells. CDKI-73 induced caspase-dependent apoptosis that was preceded by dephosphorylation of cdk9 and serine 2 of RNA polymerase II. CDKI-73 was more potent than the pan-cdk inhibitor flavopiridol and showed >200-fold selectivity against primary leukemia cells when compared with normal CD34+ cells. Furthermore, CDKI-73 was equipotent in poor prognostic sub-groups of leukemia patients and showed cytotoxic synergy with the nucleoside analog fludarabine. The Mechanism of synergy was associated with CDKI-73-mediated transcriptional inhibition of MCL1 and XIAP that was maintained when used in combination with fludarabine. Our data present a strong rationale for the development of cdk9 inhibitors such as CDKI-73 as anticancer therapeutics.
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PMID:A novel Cdk9 inhibitor preferentially targets tumor cells and synergizes with fludarabine. 2449 68

CDK (cyclin-dependent kinase) inhibitors have shown remarkable activity in CLL, where its efficacy has been linked to inhibition of the transcriptional CDKs (7 and 9) and deregulation of RNA polymerase and short-lived pro-survival proteins such as MCL1. Furthermore, ER (endoplasmic reticulum) stress has been implicated in CDK inhibition in CLL. Here we conducted a pre-clinical study of a novel orally active kinase inhibitor P1446A in CLL B-cells. P1446A inhibited CDKs at nanomolar concentrations and induced rapid apoptosis of CLL cells in vitro, irrespective of chromosomal abnormalities or IGHV mutational status. Apoptosis preceded inactivation of RNA polymerase, and was accompanied by phosphorylation of stress kinases JNK (c-Jun N-terminal kinase) and p38 MAPK (mitogen-activated protein kinase). Pharmacologic inhibitors of JNK/p38 MAPK conferred protection from P1446A-mediated apoptosis. Treatment with P1446A led to a dramatic induction of NOXA in a JNK-dependent manner, and sensitized CLL cells to ABT-737, a BH3-mimetic. We observed concurrent activation of apoptosis stress-inducing kinase 1 (ASK1) and its interaction with inositol-requiring enzyme 1 (IRE1) and tumor necrosis factor receptor-associated factor 2 (TRAF2) in CLL cells treated with P1446A, providing insights into upstream regulation of JNK in this setting. Consistent with previous reports on limited functionality of ER stress mechanism in CLL cells, treatment with P1446A failed to induce an extensive unfolded protein response. This study provides rationale for additional investigations of P1446A in CLL.
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PMID:Cyclin-Dependent Kinase Inhibitor P1446A Induces Apoptosis in a JNK/p38 MAPK-Dependent Manner in Chronic Lymphocytic Leukemia B-Cells. 2660 77

Imbalances in the composition of BCL2 family proteins contribute to tumourigenesis and therapy resistance of mantle cell lymphoma (MCL), making these proteins attractive therapy targets. We studied the efficiency of dual targeting the NOXA/MCL1 axis by combining fatty acid synthase inhibitors (NOXA stabilization) with the CDK inhibitor Dinaciclib (MCL1 reduction). This combination synergistically induced apoptosis in cell lines and primary MCL cells and led to almost complete inhibition of tumour progression in a mouse model. Apoptosis was NOXA-dependent and correlated with the NOXA/MCL1 ratio, highlighting the importance of the NOXA/MCL1 balance for effective cell death induction in MCL.
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PMID:Dual targeting of MCL1 and NOXA as effective strategy for treatment of mantle cell lymphoma. 2829 85

Anaplastic thyroid cancer (ATC) is a rare, but nearly uniformly fatal disease that is typically resistant to chemotherapy and radiation. Alternative strategies to target this cancer at a molecular level are necessary in order to improve dismal outcomes for ATC patients. We examined the effects of flavopiridol, a CDK inhibitor, in a panel of ATC cell lines. When cell lines were treated over a ten-point concentration range, CAL62, KMH2 and BHT-101 cell lines had a sub micromolar half-maximal inhibitory concentration, while no effect was seen in the non-cancerous cell line IMR-90. Flavopiridol treatment resulted in decreased levels of the cell cycle proteins CDK9 and MCL1, and induced cell cycle arrest. Flavopiridol also decreased the in vitro ability of ATC cells to form colonies and impeded migration using a transwell migration assay. In vivo, flavopiridol decreased tumor weight and tumor volume over time in a patient-derived xenograft model of ATC. Given the observed in vitro and in vivo activity, flavopiridol warrants further investigation for treatment of ATC.
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PMID:Flavopiridol causes cell cycle inhibition and demonstrates anti-cancer activity in anaplastic thyroid cancer models. 3297 Jul 4